Question

C programming

How to get rid of the below error. I do not know why is this happening and how can I correct it. Please help.

typedef struct circleroute{
char* name;
} Circle;

Circle* circlemalloc(int nroutes); //error free
Circle* readRoute(FILE* fin); //error free

int main(int argc, char* argv[]){
if(argc < 2){
if(argv[1] != NULL){
FILE *fin = fopen(argv[1], "r");
if(fin == NULL){
printf("Unable to open file %s!\n", argv[1]);
return EXIT_FAILURE;
}
int routes;
fscanf(fin, "%d", &routes);
Circle* c1= circlemalloc(routes);
for(int i = 0; i < routes; i++){
c1[i] = readRoute(fin); //This gives me an error saying incompatible types when assigning to type Circle from type struct Circle *
}
}
}
}

Circle* circlemalloc(int nroutes){
Circle* cThis = (Circle*)malloc(sizeof(Circle) * nroutes);
   return cThis;
}

Circle* readRoute(FILE* fin){
Circle* obj;
int val;
char* rName;
fscanf(fin, "%d", &val);
fscanf(fin, "%s", rName);
obj->name = rName;
return obj;
}

Answer 1

Your c1 points to Array of Pointer to Circle. So, it should be declared as Circle**. Circle* can point to only one

Circle object.

Please try the following code

#include <stdio.h>
#include <malloc.h>

typedef struct circleroute {
char* name;
} Circle;

Circle** circlemalloc(int nroutes); //error free
Circle* readRoute(FILE* fin); //error free

int main(int argc, char* argv[]) {
if (argc < 2) {
if (argv[1] != NULL) {
FILE* fin = fopen(argv[1], "r");
if (fin == NULL) {
printf("Unable to open file %s!\n", argv[1]);
return EXIT_FAILURE;
}
int routes;
fscanf(fin, "%d", &routes);
Circle** c1 = circlemalloc(routes);
for (int i = 0; i < routes; i++) {
c1[i] = readRoute(fin); //This gives me an error saying incompatible types when assigning to type Circle from type struct Circle *
}
}
}
}

Circle** circlemalloc(int nroutes) {
Circle** cThis = (Circle**)malloc(sizeof(Circle) * nroutes);
return cThis;
}
Circle* readRoute(FILE* fin) {
Circle* obj;
int val;
char* rName;
fscanf(fin, "%d", &val);
fscanf(fin, "%s", rName);
obj->name = rName;
return obj;
}