The program takes in a command for e.g. "a australia" which adds an ASCII image file with the australian flag into the node. If I type i, it gives an index of all the files added, and if I press p, it prints the flag onto the screen.
Now these 3 commands work fine to an extent. But if I press "i" to list the files and THEN press "p" it gives me a segfault, however if I don't list the files, i can add and print as many times without any problems. I'm guessing the memory allocation isn't right? But it could be the code.
Code:typedef struct country Country; struct country { char name[LENGTH]; int dimen; int num; QTnode *flag; // another structure defined in a nother file Country *next; }; char cpy( char s[MAXLENGTH], char strEd[MAXLENGTH] ); Country *makeNode(char p[MAXLENGTH]); // Main function int main( void ) { char command[MAXLENGTH]; char c; Country *node; Country *pnode; //previous node Country *curr; //the current node i.e. the most recent file added Country *tail = NULL; int dimen; int i = 1; //This is the image number int j; //This is a control number for the while loop printPrompt(); while( fgets( command, MAXLENGTH, stdin ) != NULL ) { int imgNum; char *p; if(( p=strrchr( command, '\n')) != NULL ) { *p = '\0'; // remove '\n' at end of line } // find the first non-space character in the command p = command; while(isspace(*p)) { p++; } c = *p; if( isdigit(c)) { if( sscanf( command, "%d", &imgNum ) == 1 ) { // INSERT CODE FOR <k> COMMAND } } else switch( c ) { case 'h': // help printf(" A - Add image\n" ); printf(" I - Index\n" ); printf(" P - Print image\n" ); printf(" F - Forward\n" ); printf(" B - Back\n" ); printf("<k>- make image number k the current image\n"); printf(" D - Delete image\n" ); printf(" L - Look for image\n" ); printf(" R - Rotate image counterclockwise\n" ); printf(" M - Mirror image (reflect vertically)\n" ); printf("NE - zoom into North East corner\n" ); printf("NW - zoom into North West corner\n" ); printf("SW - zoom into South West corner\n" ); printf("SE - zoom into South East corner\n" ); printf(" O - zoom Out\n" ); printf(" U - Undo\n" ); printf(" H - Help\n" ); printf(" Q - Quit\n" ); break; // INSERT CODE FOR OTHER COMMANDS case 'a': j = 1; while( j > 0 ){ //This loop is actually to allow the image number to increase everytime this case a executes. p++; while(isspace(*p)) { p++; } node = makeNode(p); //Create a new node curr = node; strcpy(node->name, p); // Copy from the user input to the member 'name' of the struct called node node->flag = getImage(node->name, &node->dimen); node->num = i; if((node->dimen > 0) && (node->dimen < 128)) { printf("*%d [%2d] %s\n", node->num, node->dimen, node->name); //Print details after adding each image } if( tail == NULL ) { tail = node; pnode = node; } else { pnode->next = node; pnode = pnode->next; } pnode->next = NULL; j = 0; i++; } break; case 'i': node = tail; while (node != NULL){ if(node == curr){ printf("*%d [%2d] %s\n", node->num, node->dimen, node->name); } else{ printf(" %d [%2d] %s\n", node->num, node->dimen, node->name); } node = node->next; } break; case 'p': //print the image dimen = node->dimen; printImage(node->flag, dimen); //accessing the inner node break; case 'q': // quit program printf("Bye!\n"); return 0; break; default: printf("Unrecognized command: %s\n", command ); break; } printPrompt(); } return 0; } Country *makeNode(char p[MAXLENGTH]){ Country *node; node = (Country*)malloc(sizeof(Country)); node->next = NULL; return (node); }
