Hi all,
I have written this piece of code: it is supposed to recieve an istream with a string which is used to create a graph.
the istream is of the follwing format:
|vertex1,vertex2, .. ,vertexn|(v1->v2),(vi->vj)..|
example:
|1,2,3|(1->2),(2->3)|
will create a graph, where 1,2,3 are vertices, and there are edges 1->2 and 2->3
however this code fails: it creates the vertices, assigns the right "source" for the edge, but put gibrish into "dest"
below is the code, I have marked the problematic line
Please help!!
Code:istream& operator >> (istream& in,Graph & g1) { //local variables char string[MAX]; char buff; int curr=0,temp,source,dest; Vertex v1; stringstream ss; /**************GET VERTECIES FROM STREAM**************************************/ //get rid of first '|' in >> (in, buff); //get first num in >> (in, buff); while (buff!='|') { //while still reading digits (not comma) while (isdigit(buff)) { string[curr]=buff; in >>(in, buff); curr++; } //have now read comma or |(is value of buff) //set ss to empty string stream ss.str(string); //convert to integer ss >> temp; //add new vertex with value g1.addVer(temp); //set pos in string to 0 curr=0; string[curr]='\0'; //read next digit if (buff!='|') in >>(in, buff); } /*********************GET EDGES FROM STREAM***********************************/ //get first "(" in >> (in, buff); while (buff!='|') { //for each edge!!!!! //flush stream ss.str(""); /********* GET SOURCE*************************/ in >> (in, buff); while (isdigit(buff)) { string[curr]=buff; in >>(in, buff); curr++; } //add source to int string[curr]='\0'; ss.flush(); ss.str(string); ss >> source; /*********FLUSH "->" ***************************/ in >> (in, buff) >> (in, buff); //at this stage, buff contains first dig of dest vertex curr=0; while (isdigit(buff)) { string[curr]=buff; in >>(in, buff); curr++; } //add dest to int string[curr]='\0'; ss.flush(); ss.str(string); ss >> dest; //HERE"S THE PROBLEM: DOESNT ASSIGN g1.addEd(source,dest); //at this stage buff contains the final ) of edge //get char after bracket (comma or |) in >> (in, buff); if (buff == ',') in >> (in, buff) >> (in,buff); } return in; }
