/******BEFORE YOU RUN****** Input a linear equation with 1 variable (Use x as the variable). This program would calculate what the variable is. **Brackets are not allowed because it's not defined in this program ;(** **************************/ //This is my first program with vectors. This code is kinda too messy for me. If you have any suggestion. Please let me know :). #include #include #include int toNum(std::string input, int &i) { int result=0; for(; input[i]>='0' && input[i]<='9' ; i++) { result*=10; result+=input[i]-'0'; } i--; return result; } int main() { std::vectornum; double xValue = 0; double result = 0; size_t eq = 0; std::string input; bool passEqual = false; getline(std::cin, input); std::cout << input; for(int i = 0 ; i= '0' && input[i] <= '9') { num.push_back(toNum(input, i)); } else { switch(input[i]) { case 'x': if(input[i-1]>='0' && input [i-1]<='9') xValue += (passEqual ? num.back() : -num.back()); else xValue += (passEqual ? 1 : -1); num.erase(num.end()-1); break; case '+': num.push_back(toNum(input, ++i)); break; case '-': num.push_back(-toNum(input, ++i)); break; case '*': if(input[i-1]=='x') xValue*=toNum(input, ++i); else *(num.end()-1)*=toNum(input, ++i); break; case '/': if(input[i-1]=='x') xValue/=toNum(input, ++i); else *(num.end()-1)/=toNum(input, ++i); break; case '=': passEqual=true; eq=num.size(); break; default: std::cout << "Invalid character."; return 0; } } } for(int i = 0 ; i <= num.size() ; i++) { if(i >= eq && passEqual) result-=num[i]; else result+=num[i]; } if(!passEqual) { std::cout << "= " << result; } else std::cout << "\nx = " << result/xValue; return 0; }

Linear equation with 1 variable