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I wrote a program that compiles, but is stopping responding during execution.
This program opens a PGM file and saves the derivative by convolution in saida.pgm.
The function LerPGM() receives a string with the filename and returns a dynamically allocated 2D array in img.
The function Convolucao() performs the convolution operation in the array img using a kernel already declared and saved in another array.
SalvarPGM() receives this other array and a string and then writes the array to a PGM file whose name is the received string.
#include <stdio.h>
#include <stdlib.h>
typedef struct{
int c;
int l;
unsigned char maximo;
unsigned char **imagem;
} PGM;
PGM *LerPGM(char* entrada);
void SalvarPGM(PGM *img, char* saida);
void Convolucao(PGM *img, char **kernel, PGM *saida);
int main()
{
PGM *imgconv;
char kernel[3][3]={{-1, 0, 1},{-1, 0, 1},{-1, 0, 1}};
if(SalvarPGM(Convolucao(LerPGM("entrada.pgm"), kernel, imgconv), "saida.pgm")) printf("Operacao realizada com sucesso.");
return 0;
}
PGM *LerPGM(char* entrada){
PGM img;
char tipo[3];
int i, j;
FILE *arq;
arq = fopen(entrada, "r");
if(arq == NULL){
printf("Arquivo nao encontrado.");
return 0;
}
fscanf(arq, "%s %d %d %d", &tipo, &img.c, &img.l, &img.maximo);
if(strcmp(tipo, "P2")){
printf("O arquivo nao e PGM.");
return 0;
}
img.imagem = malloc(img.l * sizeof(char *));
for(i=0; i<img.c; i++) img.imagem[i] = malloc(img.c * sizeof(char));
if(img.imagem == NULL){
printf("Falha na alocacao de memoria.");
return 0;
}
for(i=0; i<img.l; i++){
for(j=0; j<img.c; j++){
fscanf(entrada, "%d", &img.imagem[i][j]);
}
}
fclose(arq);
return &img;
}
void Convolucao(PGM *img, char **kernel, PGM *saida){
unsigned char aux[img->l+2][img->c+2];
int i, j, k, l, soma;
saida = img;
for(i=1; i<img->l+1; i++){
for(j=1; j<img->c+1; j++){
aux[i][j] = img->imagem[i-1][j-1];
}
}
for(i=1; i<img->l+1; i++){
aux[i][0] = aux[i][1];
aux[i][img->c+1] = aux[i][img->c];
}
for(j=0; j<img->c+2; j++){
aux[0][j] = aux[1][j];
aux[img->l+1][j] = aux[img->l][j];
}
for(i=1; i<img->l+1; i++){
for(j=1; j<img->c+1; j++){
soma=0;
for(k=2; k>=0; k--){
for(l=2; l>=0; l--){
soma+=kernel[k][l]*aux[i+(1-k)][j+(1-l)];
}
}
if(soma<=0) saida->imagem[i-1][j-1]=0;
else if(soma>=255) saida->imagem[i-1][j-1]=255;
else saida->imagem[i-1][j-1]=soma;
}
}
free(img);
free(aux);
return saida;
}
void SalvarPGM(PGM *img, char* saida){
int i, j;
FILE *arq;
arq = fopen("saida.pgm", "w");
if(arq == NULL){
printf("Ocorreu um erro.");
return 0;
}
fprintf(arq, "%s\n%d %d %d", "P2", img->c, img->l, img->maximo);
for(i=0; i<img->l; i++){
fprintf(saida,"\n");
for(j=0; j<img->c; j++){
fprintf(saida, "%d ", img->imagem[i][j]);
}
}
fclose(arq);
free(img);
return 1;
}
This program is stopping responding and I don’t know exactly why. I don’t know if I’m using the pointers wrong (or maybe the structs) or if I’m allocating them erroneously. When I don’t use functions the program works perfectly. For example:
#include <stdio.h>
#include <stdlib.h>
typedef struct{
int c;
int l;
unsigned char maximo;
unsigned char **imagem;
} PGM;
int main()
{
PGM img;
char tipo[10];
int i, j, k, kk;
FILE *entrada;
entrada=fopen("entrada.pgm", "r");
if(entrada==NULL){
printf("Arquivo nao encontrado.");
return 0;
}
fscanf(entrada, "%s %d %d %d", &tipo, &img.c, &img.l, &img.maximo);
if(strcmp(tipo, "P2")){
printf("O arquivo nao e PGM.");
return 0;
};
img.imagem=malloc(img.l * sizeof(char *));
for(i=0; i<img.c; i++) img.imagem[i]=malloc(img.c * sizeof(char));
if(img.imagem==NULL) printf("Ocorreu um erro!");
for(i=0; i<img.l; i++){
for(j=0; j<img.c; j++){
fscanf(entrada, "%d", &img.imagem[i][j]);
};
};
int kernel[3][3]={{-1, 0, 1}, {-1, 0, 1},{-1, 0, 1}};
unsigned char aux[img.l+2][img.c+2];
for(i=1; i<img.l+1; i++){
for(j=1; j<img.c+1; j++){
aux[i][j]=img.imagem[i-1][j-1];
};
};
for(i=1; i<img.l+1; i++){
aux[i][0]=aux[i][1];
aux[i][img.c+1]=aux[i][img.c];
};
for(j=0; j<img.c+2; j++){
aux[0][j]=aux[1][j];
aux[img.l+1][j]=aux[img.l][j];
};
int soma;
for(i=1; i<img.l+1; i++){
for(j=1; j<img.c+1; j++){
soma=0;
for(k=2; k>=0; k--){
for(kk=2; kk>=0; kk--){
soma+=kernel[k][kk]*aux[i+(1-k)][j+(1-kk)];
};
};
if(soma<=0) img.imagem[i-1][j-1]=0;
else if(soma>=255) img.imagem[i-1][j-1]=255;
else img.imagem[i-1][j-1]=soma;
};
};
fclose(entrada);
FILE *saida;
saida=fopen("saida.pgm", "w");
fprintf(saida, "%s\n%d %d %d", tipo, img.c, img.l, img.maximo);
for(i=0; i<img.l; i++){
fprintf(saida,"\n");
for(j=0; j<img.c; j++){
fprintf(saida, "%d ", img.imagem[i][j]);
};
};
fclose(saida);
return 0;
}
The function return type
SalvarPGMisvoidtheifinmainwon’t work.– DaviAragao